In the past, when high voltage transmission lines have been removed prior to replacement or the installation of higher capacity lines, the old lines were de-energized and removed from the tower insulators and pulley blocks set up at each insulator to contain the new wire as it was pulled in a rope or the old wire. This practice required erecting a series of pulley blocks to guide the wire as it was pulled into place and required frequent trips up and down the towers by workmen in order to install the new wire in place.